/*
* $Id: StackBlurFilter.java,v 1.2 2006/10/25 11:34:35 gfx Exp $
*
* Dual-licensed under LGPL (Sun and Romain Guy) and BSD (Romain Guy).
*
* Copyright 2006 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* Copyright (c) 2006 Romain Guy <romain.guy@mac.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jdesktop.swingx.image;
import java.awt.image.BufferedImage;
import org.jdesktop.swingx.graphics.GraphicsUtilities;
/**
* <p>A stack blur filter can be used to create an approximation of a
* gaussian blur. The approximation is controlled by the number of times the
* {@link org.jdesktop.swingx.image.FastBlurFilter} is applied onto the source
* picture. The default number of iterations, 3, provides a decent compromise
* between speed and rendering quality.</p>
* <p>The force of the blur can be controlled with a radius and the
* default radius is 3. Since the blur clamps values on the edges of the
* source picture, you might need to provide a picture with empty borders
* to avoid artifacts at the edges. The performance of this filter are
* independant from the radius.</p>
*
* @author Romain Guy <romain.guy@mac.com>
*/
public class StackBlurFilter extends AbstractFilter {
private final int radius;
private final int iterations;
/**
* <p>Creates a new blur filter with a default radius of 3 and 3 iterations.</p>
*/
public StackBlurFilter() {
this(3, 3);
}
/**
* <p>Creates a new blur filter with the specified radius and 3 iterations.
* If the radius is lower than 1, a radius of 1 will be used automatically.</p>
*
* @param radius the radius, in pixels, of the blur
*/
public StackBlurFilter(int radius) {
this(radius, 3);
}
/**
* <p>Creates a new blur filter with the specified radius. If the radius
* is lower than 1, a radius of 1 will be used automatically. The number
* of iterations controls the approximation to a gaussian blur. If the
* number of iterations is lower than 1, one iteration will be used
* automatically.</p>
*
* @param radius the radius, in pixels, of the blur
* @param iterations the number of iterations to approximate a gaussian blur
*/
public StackBlurFilter(int radius, int iterations) {
if (radius < 1) {
radius = 1;
}
if (iterations < 1) {
iterations = 1;
}
this.radius = radius;
this.iterations = iterations;
}
/**
* <p>Returns the effective radius of the stack blur. If the radius of the
* blur is 1 and the stack iterations count is 3, then the effective blur
* radius is 1 * 3 = 3.</p>
* @return the number of iterations times the blur radius
*/
public int getEffectiveRadius() {
return getIterations() * getRadius();
}
/**
* <p>Returns the radius used by this filter, in pixels.</p>
*
* @return the radius of the blur
*/
public int getRadius() {
return radius;
}
/**
* <p>Returns the number of iterations used to approximate a gaussian
* blur.</p>
*
* @return the number of iterations used by this blur
*/
public int getIterations() {
return iterations;
}
/**
* {@inheritDoc}
*/
@Override
public BufferedImage filter(BufferedImage src, BufferedImage dst) {
int width = src.getWidth();
int height = src.getHeight();
if (dst == null) {
dst = createCompatibleDestImage(src, null);
}
int[] srcPixels = new int[width * height];
int[] dstPixels = new int[width * height];
GraphicsUtilities.getPixels(src, 0, 0, width, height, srcPixels);
for (int i = 0; i < iterations; i++) {
// horizontal pass
FastBlurFilter.blur(srcPixels, dstPixels, width, height, radius);
// vertical pass
FastBlurFilter.blur(dstPixels, srcPixels, height, width, radius);
}
// the result is now stored in srcPixels due to the 2nd pass
GraphicsUtilities.setPixels(dst, 0, 0, width, height, srcPixels);
return dst;
}
}